The so-called AC charging mode and the so-called DC charging mode are known for charging an electric vehicle, specifically for charging a traction battery of an electric vehicle.
In the AC charging mode, the electric vehicle is connected, via its on-board charging device, to an electrical current and voltage supply network which provides AC voltage and alternating current, the on-board charging device carrying out the conversion to direct current. In the so-called AC charging mode, the charging speed for the traction battery is restricted. Charging times in the AC charging mode are several hours for each 100 kilometer range.
The traction battery of an electric vehicle can be charged more quickly via a DC charging mode, in which case the traction battery is not charged via the on-board charging device of the electric vehicle in the DC charging mode, but rather by virtue of the traction battery being directly connected, with the circumvention of the on-board charging device, to a charging station which is outside the vehicle and provides direct current for charging the traction battery. The DC charging mode can be used to achieve higher charging speeds than the AC charging mode, but it has hitherto not yet been possible to provide charging speeds for the traction battery of an electric vehicle in the DC charging mode which are of the order of magnitude of a refueling operation in conventional vehicles driven by internal combustion engines.
Previously known charging systems for electric vehicles which are used for the DC charging of the traction battery of electric vehicles have accordingly not been able to hitherto ensure high charging speeds since, on the one hand, the electrical network power provided by the available electrical current and voltage supply network is not sufficient under certain circumstances to provide a desired charging speed and, on the other hand, taking into account the fact that, at high charging speeds, high losses also occur and result in a high development of heat which has hitherto not been able to be sufficiently dissipated, however.
EP 2 572 431 B1, which is incorporated by reference herein, discloses a charging system for electric vehicles having a plurality of charging stations. The traction battery of an electric vehicle can be charged in the region of each charging station, the traction battery of the respective electric vehicle being able to be coupled to the respective charging station in the region of each charging station via a charging cable. The charging system in EP 2 572 431 B1, which is incorporated by reference herein, also has power electronics having a plurality of power converters in order to convert the network power provided by an electrical current and voltage supply network for the purpose of charging the traction battery of the electric vehicles.
EP 2 986 468 B1, which is incorporated by reference herein, discloses a further charging system for electric vehicles. Said document discloses a charging station to which a traction battery of an electric vehicle can be coupled via a charging cable of the charging station. The traction battery of the electric vehicle can be cooled via a heat sink provided by the charging station, specifically by virtue of the heat sink of the charging station making thermal contact with a contact-making area of the traction battery.
There is therefore a need for a charging system for electric vehicles which, from an electrical point of view on the one hand, and from a thermal point of view on the other hand, allows the electric vehicles to be charged at a high charging speed or with a charging power, in particular of more than 300 kW for each vehicle.